1. Field of the Invention
This invention relates to a frequency doubling and mixing circuit effecting a frequency doubling operation and a frequency mixing operation.
2. Description of the Prior Art
In case of effecting a frequency doubling operation and mixing operation, conventionally, an input signal frequency (local osillator frequency in this example) is doubled by a frequency doubler 51 and sent through a band-pass filter 52 to a mixer 53 as shown in FIG. 1. The signal thus sent to the mixer 53 is mixed with another signal inputted thereto. With the arrangement as shown above, however, it is required that the frequency doubler 51 and the frequency mixer 53 are structured independently of each other and the filter 52 is provided therebetween as shown in FIG. 1. Consequently, a problem exists such that the frequency characteristic cannot be provided on broad-band basis, and it is difficult to integrate the entire circuit. In addition, reduction in power consumption is difficult due to the fact that the number of circuit elements to be used becomes large, and the number of terminals is unavoidably increased because the filter is to be provided outside.
In consideration of the above-mentioned problems, an object of this invention is to provide a frequency doubling and mixing circuit in which the frequency doubling and mixing operations can be achieved by one unit of circuit.